Q:

Complete the equation of the line through (-8,8) and (1,-10). Use exact numbers.

Accepted Solution

A:
Since you know the x and y values, you just have to plug these into the linear slope-intercept equation:

y = mx + b
-10 = m(1) + b
m + b = -10
b = -10 - m

Now that we have a value for b, we can plug this into the other equation:

8 = m(-8) + b
8 = -8m + (-10 - m)
8 = -9m -10
18 = -9m
m = -2

Now that we know what m is equal to, we can plug this into our first equation to get an answer for b:

b = -10 - m
b = -10 -(-2)
b = -10 + 2
b = -8

Our final equation is y = -2x - 8